Subsequent Events (Tables)

9 Months Ended

Jun. 30, 2024

Subsequent Events [Abstract]

Schedule of Proforma

The following table reflects basic and diluted weighted average shares and net income per share on an unaudited pro forma basis giving effect to the stock split as if it had been effective for all periods presented:

	Pro Forma (Unaudited)
	Three Months Ended				Nine Months Ended
	June 30, 2024		July 2, 2023		June 30, 2024		July 2, 2023
Net income attributable to Tetra Tech	$	85,810	$	60,235	$	237,228	$	219,771
Weighted-average common shares outstanding - basic	267,575		266,155		267,255		265,940
Effect of dilutive stock options and unvested restricted stock	2,165		2,110		2,075		2,135
Shares issuable assuming conversion of convertible notes	520		—		175		—
Weighted-average common shares outstanding - diluted	270,260		268,265		269,505		268,075
Earnings per share attributable to Tetra Tech:
Basic	$	0.32	$	0.23	$	0.89	$	0.83
Diluted	$	0.32	$	0.22	$	0.88	$	0.82